For the purpose of controlling the technical process an automation device of the aforesaid kind typically contains a data block in which functions, parameters and other data for executing control sequences are specified. The data block is also referred to as a function block. The data block corresponds to an automation program or code for the sequence control system in the automation device.
When process control functions are being planned and configured, the desired automation functions for controlling the technical process are assembled, parameterized and interconnected in the form of graphical control blocks. The control blocks representing the automation functions are contained in a special program library, for example, from which they can be called. The parameterized and interconnected control blocks are equivalent to a configuration program which is subsequently supplied to a code generator which compiles the configuration program and converts it into a format which can be understood and processed by the automation device. The compiled configuration program generated by the code generator corresponds to the data block. The latter is typically subdivided into a plurality of data areas in which in particular data by means of which a specific sub-functionality can be executed is concentrated. The generated and compiled data block must subsequently be loaded into the automation device.
Usually a newly generated data block is supplied to the automation device in full, i.e. in particular complete with all its data areas, via a communication line connected to the automation device and a suitable communication service, and stored in said automation device. This normally happens during the operation of the automation device, i.e. while the latter is controlling the technical process by means of another data block stored in it. Said other data block is subsequently to be replaced by the new data block loaded into the automation device. As the data block may in certain cases, depending on the configuration on which it is based, contain a large volume of data, long load times can result when the data block is transferred to the automation device.
In contemporary instrumentation and control systems there is, however, a requirement for short generation and load times, in particular during commissioning of technical installations, in order to allow changes in the configuration, and hence also in the data block resulting therefrom, to take effect as quickly as possible in the automation device, and in the control of the technical process performed by it. Fast loading of the data block into the automation device is also made more difficult due to the fact that, between a control device for controlling the loading of the new data block, i.e. what is known as an application server, and the automation device, a plurality of communication channels are active on the communication line connecting them. Additional services that have to provide process values, alarms, etc. with very short delay times for the ongoing operation of the automation device are handled via said communication channels. Said additional services provide information relating to the current status of the process and receive suitable control commands. Said additional information and control channels have a much higher priority by comparison with the configuration channel that serves for transferring the new data block. Thus, only a limited bandwidth of the communication line is available for transferring the data of the new data block.